Process for treating fibrous material



' Patented SepblQ, 1939 um'rau STATES PATENT OFFICE PROCESS FOR TREATINGFIBBOUS Harman Howard A. Young, Westfield, N. 1., auignor, bymesne'aaignmentl, to United States Rubber Company, NcwYork, N. Y acorporation at New Jersey No Drawing. Application January 3, 1938,

Serial No. 183,091

SCIaims. -(L 91-ss terial from the bath by reason of the oppositelycharged colloidal particles of treating material contacting the fibroussurface; The ratio of treating bath to fibrous material in theseprocesses, however, is extremely high, ranging from :1 to 50:1 and over,commonly called in textile practice a long bath, while the concentrationof colloidal treating material in .such treating baths is extremely low,ranging from a few hundredths of one percent to less than two percent.In othenprocesses of treating fibrous materials with a long bath, aswith dilute latex, the rubber "particles are coagulated on the fibers bymeans of heat, or by the gradual addition of a coagulant to the bath.There are many disadvantages in using such large volumes of dilute bath.A large volume of dilute bath necessitates 39 the use of a much higheramount of protective agent for the equivalent degree of stability of agiven amount of dispersed colloidalmaterial than 45 colloidal materialto deposit upon the surface or the fibrous material and subsequently berubbed oil by mechanical friction, and, in the case of fabrics, to showstreaks, chafe marks, and socailed running marks and crows feet on the50 finished material.

' not continuous and this is of a decided disadvantage in treating longlengths of fabric.

In other processes, the fibrous material may be treated with an amountof a latex composition 65 that is less than that which will cause wetsatuping wet.

Further, such processes are ration of the fibrous material, that is, anamount which can be held by the fibrous material without permittingliquid to drain from the material when it'is hung up or draped, or an'amount less than that which would cause the material to be drip- Theamount of latex composition which usually remains held in the fibrousmaterial in such treatments, as where the fibrous ma-' terial is, passedthrough a bath of the latex composition and wrungor squeezed, as throughroll- 1 ers, or where the latex is sprayed onto the fibrous -material,is from 40% to 250% of the weight of thefibrous material. In suchprocesses, however, the rubber particles remain in dispersed conditionin the latex which is held by the fibrous material until they arecoagulated by some ex- .ternal influence, as by the drying of the latexheld in the fibrous material, or by a chemical coagulation of the latexcomposition, as by pretreating the fibrous material with a latex coagu-20 lant, or by passing the fabric with the absorbed latex through aseparate coagulating bath, or by heating the fibrous material containingthe latex composition in cases where the latex is heat sensitive, thatis, where the latex is coagulable 25 by heat. In these processes wherethe rubber is coagulated from the latex that is held in the fibrousmaterial as by drying, or bytreatment with a free coagulant, or byheating a heat 'sensitive latex composition, the rubber that is"deposited on the fibrous material becomes concentrated during thecoagulating operation on the outer surfaces of the fibrous material, andthe finished material may become stifi and boardy, and, in the case offabrics, lose the fabric feel and appearance of untreated fabric.

According to thepresent invention, fibrous material is treated with anamount of a, latex composition which is less than that required for wetsaturation of the fibrous material, and the col 40 loidal rubberparticles are deposited onto the fibrous material without the aid of anyexternal coagulating influences, thereby permitting the colloidal rubberparticles to gradually deposit on the fibers evenly throughout the bodyof the fibrous material from the inside of the material so that thefinished product while obtaining the advantages of the-rubber treatment,maintains the appearance and feel of untreated material.

In carrying out the process of the present invention, fibrous material,is treated with an amount less than that required for wet saturation ofa latex composition which will deposit substantially all its rubberparticles on the fibrous material under normally non-coagulativeconditions for the latex composition. and thereafter allowing thefibrous material with its contained latex composition to rest until thedispersed rubber particles have deposited on the fibrous material. Theamount of entrained or absorbed latex composition which will cause wetsaturation of the fibrous material differs with different kinds offibers and various types of fibrous material, but the ratio of theabsorbed latex composition to fibrous material according to the presentinvention will range with various fibrous materials and depending on theamount of rubber desired to be deposited on the fibrous material, from.4:1 to 25:1, that is, the weight of the latex composition held in thefibrous material will be 40% to 250% of the weight of the fibrousmaterial. The latex composition for treating the fibrous material shouldhave a 3 to 30% solids concentration depending on the amount of latexcomposition caused to be absorbed by thefibrous material and on theamount of rubber desired to be finally deposited on the fibrousmaterial. The latex composition which is absorbed in the fibrousmaterial is made sensitive to the fibrous mat-- rial, that is, willdeposit its colloidally dispersed rubber particles on the fibrousmaterial under otherwise non-coagulative' conditions for the latexcomposition itself, by compounding the latex treating bath so that itcontains a latex coagulant and sufficient protective so that it isitself stable under the conditions of treatment of .the fibrousmaterial, but will deposit its rubber particles on the fibrous materialwhen associated with the fibrous material. The amount of protectiveintroduced into the latex treating composition need be but slightly morethan that necessary to stabilize the latex treating composition in theabsence of the fibrous material under the conditions of treatment of thefibrous material. The greater the amount of protective used over thatnecessary to merely protect the latex composition against coagulation inthe absence oi the fibrous material by the added coagulating agent, theslower will be the deposition of the dispersed rubber particles from thecomposition onto the fibrous material when in' contact therewith. If thefibrous material is treated with the latex treating composition at roomtemperature and the fibrous material with the latex held therein ispermitted to rest at room tem-' perature until the dispersed rubberparticles have deposited on the fibers, the amount of protective agentin the latex composition need be only that amount or slightly more thanthat which is necessary to protect the latex composition itself at roomtemperature. If the fibrous material is treated with the latexcomposition at elevated temperature, then the amount of protective mustbe such that it will stabilize the latex composition in the presence ofthe added coagulant at such elevated temperature, otherwise the latextreating bath will coagulate before being absorbed into the fibrousmaterial. Likewise if the fibrous material is treated with the latextreating composition at room temperature and allowed to rest at elevatedtemperaure, in order to speed up the deposition of the rubber onto thefibrous material, the amount of protective must again be such that thelatex composition itself is stable at such elevated temperature,otherwise the rubber will not be allowed to deposit gradually on thefibers of the fibrous material but the latex composition will coagulateat the elevated temperature of the rest period and produce an unevensurface coagulation. Of course the treatment of the fibrous -materialwith the latex should be carried out under all other normallynon-coagulative conditions for the latex treating composition, that is,without coagulation by outside influence, as for example, drying, or thepresence of free coagulant on the fibers, or passing of the fibrousmaterial impregnated with the latex treating bath through a coagulantmedium.

I have developed a theory for my invention which explains thesensitivity to a fibrous material of an otherwise noncoagulating latexcomposition, and this I am setting forth with the idea of clarifying theprocess, but without the intention of making the invention in the casedependent upon the correctness of this theory. I believe that when afibrous material holds its entire treating bath, that is, contains an.amount less than its wet saturation," of a latex composition of asolids concentration of dispersed particles as high as 3 to 30% andcontains a coagulant and protective in accordance with the presentinvention, the fibrous material gradually absorbs the protective fromthe latex composition and causes a deposition of the colloidal rubberparticles which are then in the presence of a coagulant but are nolonger protected from the coagulant by the protective which has beenabsorbed by the fibrous material, so that there is gradually built upwith the absorption by the fibers of the protective agent, a depositionof the no longer protected rubber particles. It has been found that thecoagulant that is introduced into the latex composition and againstwhich the .colloidally dispersed rubber particles are protected in theabsence of the fibrous material maybe an alkaline or acid coagulant sothat the deposition of the dispersed rubber particles on the fibrousmaterial is not necessarily dependent on any type of charge on thecolloidal rubber particles or on the fibrous material.

Various types of fibrous materials, such as woven, knitted, punched, orfelted fabrics, yarns, rovings, cords, skeins, and .webs such aswaterlaid felts from a paper making machine or bats of fibers from aGarnett or carding machine, may

be treated according to the present invention. Various fibers, as ofwool, silk, cotton, viscose or acetate rayon, linen, cellulose and thelike may be used and these may be undyed, mordanted, dyed or otherwisetreated so long as they are not associated with free coagulant which inthe absence of the fiber would itself produce coagulaotherwise treatedas desired, as by vulcanization,

and which may be in a normal, diluted, concentrated or purifiedcondition prduced by methods well known in the art.

Various examples of the treatment of different fibrous materials withlatex compositions protected with various known stabilizers andcontaining a coagulant according to the present invention are set forthbelow, but these are merely exemplary of the invention and are notintended to be limitations thereon. Common latex protectives that may beused are proteins, gums, soaps,

vegetable mucilages, saponin, starch, and certain v salts oi carboxyl(it-0001b, 'sulphonic (RF-Bonn), sulphinic (R SO:M), or phenolic groupsor of ethereal sulphuric (R-OM) (RQSOaM) radicals, where the R may havea straight chain or ring structure and may contain substituent halogen,amino, nitro. or hydroxyl groups. Other organic chemicals are well knownprotectives as certain benzene-sulphonic acids, their homologues andsubstitution'prodl0 ucts, naphthoic acids, aliphatic-aromatic-acids,

derivatives of hydro-aromatic series of acids. phenylglycine andderivatives.

. In order to better understand the invention, the followingillustrative examples are included.

7 In these examples, the selected fabric was passed through the latextreating bath so that it became thoroughly wetted by the latex, and thedesired amount of latex was removed by passing inthe flat throughsqueeze rolls. The amount of latex composition remaining absorbed in thedesired period of time, which in practice canecon- 0 veniently beanything up to 60 minutes during which time the'dispersed particles ofrubber deposited in and upon the fibers. The duration 'of this resttreatment for depositing a desired proportion, or all, of the dispersedrubber particles,

can 7 be governed by the composition of the bath, commonly by theconcentration of the latex composition and the amount of protective usedover that necessary to prevent coagulation of the latex in the presenceof the coagulant contained 40 therein but in the absence of the fibrousmaterial.

In practice, however, it is a simple matter to determine the amount ofrubber not deposited from the latex composition by squeezing a part ofthe fabric at time intervals by hand and noting the characteristics ofthe expressed liquid, such as turbidity, or by rinsing samples of thefabric and noting the degree of turbidity ofthe rinse water. Elevatedtemperatures, which in the absence of the fibrous material, would notcause coagulation of the latex composition, may be used and thus speedup the deposition of solids from the latex onto the fibrous material.After the desired amount of ruhber'has deposited from the latex onto thefibrous material, the thus treated material may be washed, dried, therubber deposit vulcanized if desired, and the material finished. Thereis an additional distinct-advantage here over methods of treatment wherethe entrained latex must be dried to form the deposit on the fibrousmaterial and where the thus dried material is subsequently washed andredried. In such practice two dryings are necessary whereas according tothe present invention only one drying operation need be performed due tothe deposition of the rubber onto the fibers in the wet condition andthe consequent possibility of washingthe treated'material without apreliminary drying for setting the same. Formlc acid is the coagulantused in compounding the latex treating baths in the following examplesbecause it is a volatile acid, but other acids, namely acetic,

lactic, tartaric, phosphoric, hydrochloric, and

sulphuric acid have successfully been used, as well as various acidicand basic coagulating salts. J

C, lnl'mplel The latex compound for use in preparing the treatingbathwas made up as follows:

' weight Rubber (as 60% centrifuged ammonia pre served latex) Potassiumhydroxide (as 25% aqueous solution) i 2 1 Glue (as 25% aqueous solution).4 Aquarex D (as 10% aqueous solution)..- 1.25 Paste (as 35% aqueouspaste): ,5 Mercaptobenzothiazole Dimethylammonium dimethyl dithio- 15carbamate Solubilized casein 4 Colloidal sulphur 2 Zinc oxide 2.5

BLE l 5 so Water to final total solids of 40%. r

The aqueous solutions of potassium hydroxide,

glue and Aquarex D were added to the centrifuged latex and to this wasadded the remaining materials in the form of a 35% aqueous paste, afterwhich the wholelwas diluted with water to a final total solids of 40%.The "Aquarex D is a stabilizer having the composition, monosodiumsulphate ester of one-half lauryi and one- 30 half myristalalcohol. Themercaptobenzothiazol M and dimethylammonium dimethyl dithiocarbamate arevulcanization accelerators. 'BLE is the trade name of an antioxidantwhich is a condensation product of acetone and diphenylamine. The casein.in the above paste was solubilized by means of a small amount of boraxand sodium fluoride in a manner well known in the art.

A latex treating bath of the composition set forth below was made upfrom the above compound by diluting with water and adding a coagulantafter the addition of an amount of protece tive or stabilizer sufficientto" prevent coagulation of the treating bath by the added coagulant. Ifdesired, the entire amountof'stabilizer, with or without the acid, maybeadded in compounding the original latex, and merely water, or water andacid as the case may be, mixed with the latex compound to produce thetreating bath.

Wool flannel fabric was run through the above latex treating bath andsqueezed through rollers so that it contained about of its weight of thetreating bath, that is, the so-called bath-togoods ratio wasapproximately 12:1. The fabric with the thus absorbed latex compositionwas al- Bil lowed to stand at room temperature for 60 min utes, inwhichtime substantially all the rubber as deposited on the fabric asshown by a clear rinse.

The fabric after rinsing anddrying showed a gain in weight of 12.2%.Sulphano "is the trade name of a stabilizer which is a snlphated fattyalcohol. 7n

Example 2 In this case, the latex compound of Example 1 was made up intoatreatingbath usinga different rotective from the Sulphanol" used in mSolidsby Example 1. The treating bath in this case had the toilowingcomposition:

Parts by weight Solids of the latex compound of Example 1-- 10' NopalcolNo. 2"

Formic acid 5 Water- 79.7

Wool flannel fabric was run through the .above latex treating bath andsqueezed through rollers so that it contained about of its weight of thetreating bath, that is, the bath-to-goods ratio was approximately .85:1.The thus treated fabric was allowed to stand at room temperature for 15minutes, in which time substantially all the rubber deposited on thefabric, as shown by a clear rinse. The fabric after rinsing and dryingshowed a gain in weight of 8.5%. "Nopalcol No. 2 is the trade name of astabilizer which is believed to be a sulphated oil.

Example 3 Fabrics composed of fibers of more than one kind may betreated according to the present invention. In this case a paper machinewoven felt with a cotton warp and a wool filling was treated with alatex composition made from the latex compound of Example No. 1. Inpreparing the treating bath, the same stabilizer, Aquarex D", was usedto prevent coagulation on addition of the coagulant that was used incompounding the original latex. The composition of the treating bath inthis case was as follows:

Parts by weight Solids of latex compound of Example 1 12 "Aquarex D" 2Formic acid 12 Water 74 The paper machine felt was run through the abovetreating bath and squeezed through rollers so that it contained about130% of its weight of the treating bath, that is, the bath-to-goodsratio was approximately 13:1. The thus treated felt was allowed to standat room temperature for 60 minutes with no sensible reduction of watercontent, in which "time substantially all the rubber deposited on thefabric, as shown by a clear rinse. The fabric after rinsing and dryingshowed a gain in weight of 16.1%.

The treatment of other fibrous materials than wool is illustrated inExamples 4 to 6.

Erample 4 Silk fabric was treated according to the present inventionwith a treating hath made. from the latex compound of Example 1 havingthe following composition:

' Parts by weight Solids of latex compound of Example 1' 10 Aquarex D";.4 Formic acid .5 Water 89.1

The silk fabric was run through the above treating bath and squeezedthrough rollers so that it contained about 150% of its weight of thetreating bath, that is, the bath-t -goods ratio -was approximately 15:1..The fabric with the contained latex was allowed to stand at roomtemperature for 20 minutes, in which time substantially all the rubberdeposited on the fabric, and the fabric after rinsing and drying showedagain in weight of 15.2%.

Example 5 A cotton fabric was run through the treating bath of Example 4and squeezed through rollers so that it contained about of its weight ofthe treating-bath, that is, the bath-to-goodsratio .was approximately.95: 1; The thus treated fabric was allowed to stand for 20 minutes atroom temperature. After rinsing and drying the fabric showed a gain inweight of 8.5%. The rinse was slightly hazy, and in the 20 minute periodapproximately 90% of the rubber in the treating bath had deposited onthe fabric.

Example 6 In this example, a so-called immunized cotton fabric wasrunthrough the treating bath of Example 4 and squeezed through rollerssothat it contained about of its weight of the treating bath, that is,the bath-to-goodsratio was approximately 1:1. The thus treated fabricwas allowed to stand 20 minutes at room tem-' perature in which timesubstantially all the rubber deposited on the fabric as shown by a clearrinse. The fabric after rinsing and drying showed a gain in weightof'9.6%.

Various latex treating compositions can. of course, be used, anddifferent latex compounds from those used in Examples 1 to 6 are usedfor preparing the treating baths of Examples 7 and 8. In addition, theseexamples show the treatment of other materials than those treated inExamples 1 to 6.

Example 7 carbamate 1 Zinc oxide ,5 Agerite Alba .5 Colloidal sulphur 5UBIE" I -5 Gum arable 1 Gum arabic (as 10% aqueous solution) 1 Water tofinal total solids of 35%.

The stabilizing solutions of gum arabic and Aquarex D" were added to thelatex and to this was added the separately prepared paste of curingingredients- To this was added more gum arabic solution as shown by theabove formula and'the whole was diluted with water to 35% solidscontent. Darvan is the trade name of a stabilizer sold by R. T.Vanderbilt Co. which is believed tobe a sulphonated naphthalenederivative, The

tetramethyl thiurammonosulphide and piperidinium p'entam'ethylenedithiocarbamate are vulcanization accelerators. Agerite Alba" is thetrade name of an antioxidant made by R. T. Vanderbilt Co. and which issaid to be a complex phenolic compound containing carbon, hydrogenandoxygen.

The treating bath made up from the abovelatex had the followingcomposition:

Parts by weight Solids of above latex compound 10 Vultamol" 1.3 Formicacid 1.7 Water 87 The rayon fabric was passed through the above proarraase treating bath and squeezed through rollers so that with theentrainment of this competition it contained about 80% of its weight ofthe treating bath that is, the bath-to-goods ratio was apately .8:1. Thethus treated fabric was allowed to stand at room temperature for 20minutes, in which time substantially all the rubber deposited on thefabric as shown by a clear rinse. After rinsing and drying, the fabricshowed a gain in weight of 8.2%. Vultamol is the trade name of aprotective or stabilizer which is believed to be a sulphated oil.

Example 8 In this example, a cotton fabric which was tanned was used.The-cotton was tanned by soaking the fabric for two hours in a 1% tannicacid solution at 140 F.,' wringing, and drying; then soaking forone-half hour in 5% tartar emetic solution, rinsingso that it containedno free coagulant, wringing and drying.

The latex compound from which the treating bath was prepared was made upas follows:

. Water to final total solids of 35%.

The Aquarex D solution was added to the latex for stabilizing purposesand to this was added the separately prepared paste of curingingredients.

The whole was then diluted with Water to 40% solids content. Thezinc-'dimethyl dithiocarbamate is a vulcanization accelerator.

The treating bath was prepared from the above compound to have acomposition as follows:

. Parts by weight Solids of above latex compound l0 Aquarex D .2 Formicarid 15 Water 74.8

I The tanned. cotton fabric was passed through the above treating bathand squeezed through rollers so that it contained about of its weight ofthe treating bath, that is, the bath-to goods ratio was approximately37:1. The fabric with the thus contained latex composition was allowedto I stand at room temperature for 20 minutes, in which timesubstantially all the rubber deposited on the fabric. After rinsing anddrying, the fabric showed a gain in weight of 6.9%.

The application of the present invention to artificial dispersions ofrubber and synthetic rubber like materials is illustrated in Examples 9and 10.

' Example 9 In this case the treating bath was made from an artificialdispersion of crude rubber dispersed on rosin soap. The formula for thedispersion was as follows:

Water to final total solids of 50%,

The dispersion was made up in the usual manner of mixing the rosin andsodium hydroxide dispersing materials into the crude rubber afterplasticialng, andadding water until an inversion of phase, wherein therubber became dispersed inthe water, and adding further water to diluteto 50% total solids content.

The treating bath was made up from the above dispersion compound as inthe previous examples by diluting the water and acidifying in thepresence of the added stabilizer. The composition of the treating bathwas as follows:

- Parts by weight Solids 01 above dispersion compound 10 Aquarex D" -1 2Formic acid 20 Water 68 Silk fabric was run through the above treatingbath and squeezed through rollers so that it contained about of itsweight of the treating bath, that is, the bath-to-goods ratio wasapproximately 12:1. The thus treated fabric was allowed to stand at roomtemperature for-20 minutes, in which time substantially all the rubberdeposited on the fabric. The fabric after rinsing and drying showed again in weight of Example Ii) In this case a wool fabric was treatedwith an aqueous dispersion of chloro-Z-butadiene 1-3. Commercial DupreneLatex Type 50 sold by E. I. du Pont de Nemours 8: 00., Inc., and whichis an aqueous dispersion of polymerized chloro-2- butadiene, 1-3 orso-called chloroprene was used. This dispersion is stated by themanufacturer to have the following composition:

, Parts by weight Polymerized chloroprene 45 Antioxidant-Neozone L.-0.56 Sodium olea 0.9 Aqua, ammonia 1 Water 52.54

The composition of the Neozone L is not known.

A treating bath was made up from the Duprene Latex Type'50 according tothe following The wool fabric was passed through the above 1y 1.1:1. Thethus treated wool fabric was allowed to stand at room temperature for 20minutes, in which time substantially all the dispersed solids of thetreating bath deposited on the fabric. The fabric after rinsing anddrying showed a gain in weight of 10.6%.

The above, examples clearly illustrate the present invention and it willbe obvious to those smiled in the art that various other treating bathsthan those illustrated in the above examples and stabilized againstcoagulation in the absence of the fabric and sensitized to deposition inthe presence of fibrous materials, may be developed using the principlesof the present invention. In view of the many changes and modificationsthat may be 250% or the weight of the fibrous material and which'is lessthan that required for "wet saturation oi the fibrous material so thatthe fibrous material holds its entire treating bath, the treating bathbeing capable of depositing on the fibrous material in which it is heldsubstantially all its dispersed rubber particles under normallynon-coag'ulative conditions for the latex composition, and maintainingthe treating bath in the fibrous material under normally non-coagulativeconditions for the latex composition until the desired amount of rubberhas deposited on the fibrous material,

2. The process which'comprises associating fibrous material with a latexcomposition having a 3% to 30% solids concentration, causing the fibrousmaterial to entrain therein an amount of said latex composition whichranges from 40% to 250% of the weight of the fibrous material and whichis less than that required for "wet saturation of the fibrous materialso that the fibrous material holds its entire treating bath, thetreating bath being capable of depositing substantially all itsdispersed rubber particles under normally non-coagulative conditions forthe latex composition on the fibrous material in which it is held, andmaintaining the treating bath in the fibrous material under normallynon-coagulative conditions for the latex composition until substantiallyall the rubber has deposited on the fibrous material.

3. The process which comprises associating fibrous material with a latexcomposition having a 3% to 30% solids concentration, causing the fi-,

brous material to entrain therein an amount or said latex compositionwhich ranges irom 40% to 250% or the weight of the fibrous material andwhich is less than that required for "wet saturation of the fibrousmaterial so that the fibrous material holds its entire treating bath,said latex composition containing a coagulant and an amount ofprotective that stabilizes the latex composition in the absence oi thefibrous material but not in the presence of the fibrous material, thetreating bath being capable of depositing on the fibrous material inwhich it is held substantially all its dispersed rubber particles undernon-coagulative conditions for the latex composition itseli', andmaintaining the treating bath in the fibrous material undernon-coagulative conditions for the latex composition itself until thedesired amount of rubber has deposited on the fibrous material.

4. The process which comprises associating fibrous material with a latexcomposition having a 3% to 30% solids concentration, causing the fibrousmaterial to entrain therein an amount of said latex composition whichranges from 40% to 250% of the weight of the fibrous material and whichis less than that required for "wet saturation of the fibrous materialso that the fibrous materialholds its entire treating bath, sa d latexcomposition containing a coagulant and M" amount or protective thatstabilizes the latex composition in the'absence oi the fibrous materialbut not in the presence of the fibrous material, the treating bath beingcapable oi depositing on the fibrous material in which it is heldsubstantially all its dispersed rubber particles under noncoagulativeconditions for the latex composition itself, and maintaining thetreating bath in the fibrous material under non-coagulativeconditions'ior the latex composition itseli until substantiallyaall therubber has deposited on the i1- brous material.

5. The process which comprises associating fibrous material with a latexcomposition having a 3% to 30%solids concentration, causing the fibrousmaterial to entrain therein an amount 01' said latex composition whichranges from 40% to 250% of the weight of the fibrous'material and whichis less than that required for "wet saturation" or the fibrous materialso that the fibrous material holds its entire treating bath, said latexcomposition containing a coagulant and an amount of protective thatstabilizes the latex composition at room temperature in the absence ofthe fibrous material but not in the presence of the fibrous material,the treating bath being capable of depositing on the fibrous material inwhich it is held substantially all its dispersed rubber particles atroom temperature and in the absence or free coagulant on the fibrousmaterial, and maintaining the treating bath in the fibrous material atroom temperature in the absence of tree coagulant on the fibrousmaterial until the desired amount oi! rubber has deposited on thefibrous materiaL- 6. The process which comprises associating fibrousmaterial with a latex composition having a 3% to 30% solidsconcentration. causing the fibrous'material to entrain therein an amount01' said latex composition which ranges from 40% to 250% of the weightof the fibrous material and which is less than that required for "wetsaturation of the fibrous material so that the fibrous material holdsits entire treating bath, said latex composition containing a coagulantand an amount of protective that stabilizes the latex composition atroom temperature in the absence the fibrous material but not in thepresence 01' the fibrous material, the treating bath being capable ofdepositing on the fibrous material in which it is held substantially allits dispersed rubber particles at room temperature and in the absence oifree coagulant on the fibrous matrial, and maintaining the treating bathin the fibrous material at room temperature in the absence of \ireecoagulant on the fibrous material until substantially all the rubber hasdeposited on the fibrous material.

'7. The process which comprises associating fibrous material with alatex composition having a 3% to 30% solids concentration, causingthefibrous material to entrain therein an amount of said latex compositionwhich ranges from 40% to 250% of the weight of the fibrous material andwh ch is less than that required for "wet saturation" of the fibrousmaterial so that the fibrous material holds its entire treating bath,said latex composition containing a coagulant and an amount 01protective that stabilizes the latex composition at elevated temperaturein the absence of the fibrous material but not in the presence of thefibrous material, the treating bath being capable of depositing on thefibrous material in which it is held substantially all its dis- 76' 250%of the weight of the fibrous material and which is less than thatrequired for "wet saturation of the fibrous material so that the fibrouscomposition at material holds its entire treating bath, said latexcomposition containing a coagulant and an amount of protective thatstabilizes the latex sence of the fibrous material but not in thepresence of the fibrous material, the treating bath being capable ofdepositing on the fibrous material in which it is held substantially allits dispersed rubber particles at elevated temperature and in theabsence of free coagulant on the fibrous material,. and maintaining thetreating bath in the fibrous material at elevated temperature withoutdrying and in the absence offree coagulant on the fibrous material untilsubstantially all the rubber has deposited on the fibrous material.

HOWARD A. YOUNG.

elevated temperature in {the ab-

